Airfoil with baffle having flange ring affixed to platform

ABSTRACT

An airfoil includes an airfoil section that has an airfoil wall that defines leading and trailing ends and first and second sides that join the leading and trailing ends. The first and second sides span in a longitudinal direction between first and second ends. The airfoil wall circumscribes an internal core cavity. A platform is attached with the first end of the airfoil wall. The platform includes an opening that opens into the internal core cavity and a land region that circumscribes the opening. A baffle is formed of a tube and an attachment portion. The tube extends in the internal core cavity and the attachment portion has a flange ring that is affixed to the platform at the land region.

BACKGROUND

A gas turbine engine typically includes a fan section, a compressorsection, a combustor section and a turbine section. Air entering thecompressor section is compressed and delivered into the combustionsection where it is mixed with fuel and ignited to generate a high-speedexhaust gas flow. The high-speed exhaust gas flow expands through theturbine section to drive the compressor and the fan section. Thecompressor section typically includes low and high pressure compressors,and the turbine section includes low and high pressure turbines.

The high pressure turbine drives the high pressure compressor through anouter shaft to form a high spool, and the low pressure turbine drivesthe low pressure compressor through an inner shaft to form a low spool.The fan section may also be driven by the low inner shaft. A directdrive gas turbine engine includes a fan section driven by the low spoolsuch that the low pressure compressor, low pressure turbine and fansection rotate at a common speed in a common direction.

SUMMARY

An airfoil according to an example of the present disclosure includes anairfoil section that has an airfoil wall that defines leading andtrailing ends and first and second sides that joins the leading andtrailing ends. The first and second sides span in a longitudinaldirection between first and second ends. The airfoil wall circumscribesan internal core cavity. A platform is attached with the first end ofthe airfoil wall. The platform includes an opening that opens into theinternal core cavity and a land region circumscribing the opening. Abaffle is formed of a tube and an attachment portion. The tube extendsin the internal core cavity and the attachment portion has a flange ringaffixed to the platform at the land region.

In a further embodiment of any of the foregoing embodiments, the tubeand the attachment portion are connected to each other at a weld joint.

In a further embodiment of any of the foregoing embodiments, the tubeand the attachment portion overlap at the weld joint.

In a further embodiment of any of the foregoing embodiments, the weldjoint is continuous around the tube.

In a further embodiment of any of the foregoing embodiments, theattachment portion includes a tapered neck portion, and the tapered neckportion is connected to the tube at the weld joint.

In a further embodiment of any of the foregoing embodiments, the tubeand the tapered neck portion overlap at the weld joint.

In a further embodiment of any of the foregoing embodiments, the tubedefines a first tube end and a second tube end. The first tube end isconnected in the weld joint, and further includes a cover connected tothe second tube end.

In a further embodiment of any of the foregoing embodiments, the flangering has four perimeter apexes.

In a further embodiment of any of the foregoing embodiments, theattachment portion includes a tapered neck portion, and the tapered neckportion and the tube are connected to each other at a weld joint.

A gas turbine engine according to an example of the present disclosureincludes a compressor section, a combustor in fluid communication withthe compressor section, and a turbine section in fluid communicationwith the combustor. The turbine section has a turbine airfoil accordingto any of the foregoing embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The various features and advantages of the present disclosure willbecome apparent to those skilled in the art from the following detaileddescription. The drawings that accompany the detailed description can bebriefly described as follows.

FIG. 1 illustrates an example gas turbine engine.

FIG. 2 illustrates an airfoil of the engine of FIG. 1 .

FIG. 3 illustrated a sectioned view of the airfoil of FIG. 2 .

FIG. 4A illustrates an isolated view of a baffle of the airfoil fromFIG. 2 .

FIG. 4B illustrates an expanded view of the baffle of FIG. 4A.

FIG. 5 illustrates a sectioned view through a weld joint of the baffleof FIG. 4A.

FIG. 6 illustrates a sectioned view of a portion of the platform,airfoil section, and baffle of the airfoil of FIG. 2 .

FIG. 7A illustrates an isolated view of another example baffle.

FIG. 7B illustrates an expanded view of the baffle of FIG. 7A.

DETAILED DESCRIPTION

FIG. 1 schematically illustrates a gas turbine engine 20. The gasturbine engine 20 is disclosed herein as a two-spool turbofan thatgenerally incorporates a fan section 22, a compressor section 24, acombustor section 26 and a turbine section 28. The fan section 22 drivesair along a bypass flow path B in a bypass duct defined within a nacelle15, and also drives air along a core flow path C for compression andcommunication into the combustor section 26 then expansion through theturbine section 28. Although depicted as a two-spool turbofan gasturbine engine in the disclosed non-limiting embodiment, it should beunderstood that the concepts described herein are not limited to usewith two-spool turbofans as the teachings may be applied to other typesof turbine engines including three-spool architectures.

The exemplary engine 20 generally includes a low speed spool 30 and ahigh speed spool 32 mounted for rotation about an engine centrallongitudinal axis A relative to an engine static structure 36 viaseveral bearing systems 38. It should be understood that various bearingsystems 38 at various locations may alternatively or additionally beprovided, and the location of bearing systems 38 may be varied asappropriate to the application.

The low speed spool 30 generally includes an inner shaft 40 thatinterconnects, a first (or low) pressure compressor 44 and a first (orlow) pressure turbine 46. The inner shaft 40 is connected to the fan 42through a speed change mechanism, which in exemplary gas turbine engine20 is illustrated as a geared architecture 48 to drive a fan 42 at alower speed than the low speed spool 30. The high speed spool 32includes an outer shaft 50 that interconnects a second (or high)pressure compressor 52 and a second (or high) pressure turbine 54. Acombustor 56 is arranged in exemplary gas turbine 20 between the highpressure compressor 52 and the high pressure turbine 54. A mid-turbineframe 57 of the engine static structure 36 may be arranged generallybetween the high pressure turbine 54 and the low pressure turbine 46.The mid-turbine frame 57 further supports bearing systems 38 in theturbine section 28. The inner shaft 40 and the outer shaft 50 areconcentric and rotate via bearing systems 38 about the engine centrallongitudinal axis A which is collinear with their longitudinal axes.

The core airflow is compressed by the low pressure compressor 44 thenthe high pressure compressor 52, mixed and burned with fuel in thecombustor 56, then expanded over the high pressure turbine 54 and lowpressure turbine 46. The mid-turbine frame 57 includes airfoils 59 whichare in the core airflow path C. The turbines 46, 54 rotationally drivethe respective low speed spool 30 and high speed spool 32 in response tothe expansion. It will be appreciated that each of the positions of thefan section 22, compressor section 24, combustor section 26, turbinesection 28, and fan drive gear system 48 may be varied. For example,gear system 48 may be located aft of the low pressure compressor, or aftof the combustor section 26 or even aft of turbine section 28, and fan42 may be positioned forward or aft of the location of gear system 48.

The engine 20 in one example is a high-bypass geared aircraft engine. Ina further example, the engine 20 bypass ratio is greater than about six(6), with an example embodiment being greater than about ten (10), thegeared architecture 48 is an epicyclic gear train, such as a planetarygear system or other gear system, with a gear reduction ratio of greaterthan about 2.3 and the low pressure turbine 46 has a pressure ratio thatis greater than about five. In one disclosed embodiment, the engine 20bypass ratio is greater than about ten (10:1), the fan diameter issignificantly larger than that of the low pressure compressor 44, andthe low pressure turbine 46 has a pressure ratio that is greater thanabout five 5:1. Low pressure turbine 46 pressure ratio is pressuremeasured prior to inlet of low pressure turbine 46 as related to thepressure at the outlet of the low pressure turbine 46 prior to anexhaust nozzle. The geared architecture 48 may be an epicycle geartrain, such as a planetary gear system or other gear system, with a gearreduction ratio of greater than about 2.3:1 and less than about 5:1. Itshould be understood, however, that the above parameters are onlyexemplary of one embodiment of a geared architecture engine and that thepresent invention is applicable to other gas turbine engines includingdirect drive turbofans.

A significant amount of thrust is provided by the bypass flow B due tothe high bypass ratio. The fan section 22 of the engine 20 is designedfor a particular flight condition—typically cruise at about 0.8 Mach andabout 35,000 feet (10,668 meters). The flight condition of 0.8 Mach and35,000 ft (10,668 meters), with the engine at its best fuelconsumption—also known as “bucket cruise Thrust Specific FuelConsumption (‘TSFC’)”—is the industry standard parameter of lbm of fuelbeing burned divided by lbf of thrust the engine produces at thatminimum point. “Low fan pressure ratio” is the pressure ratio across thefan blade alone, without a Fan Exit Guide Vane (“FEGV”) system. The lowfan pressure ratio as disclosed herein according to one non-limitingembodiment is less than about 1.45. “Low corrected fan tip speed” is theactual fan tip speed in ft/sec divided by an industry standardtemperature correction of [(Tram ° R)/(518.7° R)]{circumflex over ( )}5.The “Low corrected fan tip speed” as disclosed herein according to onenon-limiting embodiment is less than about 1150 ft/second (350.5meters/second).

FIG. 2 illustrates a representative example of a turbine airfoil 60 usedin the turbine engine 20 (see also FIG. 1 ), and FIG. 3 illustrates asectioned view of the airfoil 60. As shown, the turbine airfoil 60 is aturbine vane; however, it is to be understood that, although theexamples herein may be described with reference to the turbine vane,this disclosure is also applicable to turbine blades.

The turbine airfoil 60 includes an outer or first platform 62, an inneror second platform 64, and an airfoil section 66 that spans in alongitudinal direction A1 (which is also a radial direction relative tothe engine central axis A) between the first and second platforms 62/64.Terms such as “radially,” “axially,” or variations thereof are usedherein to designate directionality with respect to the engine centralaxis A.

The airfoil section 66 includes an airfoil outer wall 68 that delimitsthe profile of the airfoil section 66. The outer wall 68 defines aleading end 68 a, a trailing end 68 b, and first and second sides 68c/68 d that join the leading and trailing ends 68 a/68 b. The first andsecond sides 68 c/68 d span in the longitudinal direction between firstand second ends 68 e/68 f. The first and second ends 68 e/68 f areattached, respectively, to the first and second platforms 62/64. In thisexample, the first side 68 c is a pressure side and the second side 68 dis a suction side. As shown in FIG. 3 , the outer wall 68 circumscribesan internal core cavity 70. In this example, the airfoil section 66includes a rib 72 that extends from the first side 68 c to the secondside 68 d and partitions the cavity 70 into a forward core cavity 70 aand an aft core cavity 70 b.

A baffle 74 is disposed in the internal core cavity 70. In this example,the baffle 74 is in the forward core cavity 70 a. During operation,cooling air, such as bleed air from the compressor section 24, isprovided to the baffle 74 through the first platform 62. The baffle 74facilitates distribution of the cooling air in the forward core cavity70 a to cool the outer wall 68 at and near the leading end 68 a. Forinstance, the baffle 74 may include impingement orifices through whichthe cooling air flows to impinge on the inside surface of the outer wall68 for cooling.

FIG. 4A shows an isolated view of the baffle 74, and FIG. 4B shows anexpanded view of the various sections of the baffle 74. The baffle 74 isformed at least of a tube 76 and an attachment portion 78. In thisexample, there is also a cover 80. The tube 76, attachment portion 78,and cover 80 may be made of a metallic alloy, such as a nickel- orcobalt-based alloy.

The tube 76 has a shape that is generally congruent with the shape ofthe forward core cavity 70 a. The tube 76 includes a first tube end 76 aand a second tube end 76 b. The attachment portion 78 includes a flangering 82 that circumscribes an open central region 84. For instance, theflange ring 82 is a continuous or endless band that circumscribes theopen central region 84. In this example, the attachment portion 78 alsoincludes a tapered neck portion 86. For instance, the tapered neckportion 86 is a funnel or funnel-shaped.

The tube 76 and the attachment portion 78 are connected to each other ata weld joint 88. For instance, in this example, the tapered neck portion86 is connected to the first tube end 76 a of the tube 76 at the weldjoint 88, and the weld joint 88 is continuous around the tube 76. FIG. 5illustrates a sectioned view through a representative portion of theweld joint 88. For example, the weld joint 88 may include a weld bead 88a that bonds the tapered neck portion 86 and the tube 76 together. Theweld bead 88 a may be a weld material that is provided separately fromthe attachment portion 78 and the tube 76 during a welding process, oran amalgamation of the material of the attachment portion 78 and thetube 76 from melting during a welding process. The weld joint 88provides a continuous, airtight bond and seal between the tube 76 andthe attachment portion 78.

In this example, the tube 76 and the tapered neck portion 86 of theattachment portion 78 overlap at the weld joint 88. Such an overlap mayfacilitate strengthening of the region of the weld joint 88. In thisexample, the tapered neck portion 86 is outside of the tube 76. However,it is to be understood that alternatively the tube 76 may be outside ofthe tapered neck portion 86. The cover 80 is connected to the secondtube end 76 b. For example, the cover 80 is welded to the tube 76 atanother weld joint 89 (FIG. 4A).

FIG. 6 illustrates a sectioned view through a representative portion ofthe airfoil section 66, first platform 62, and baffle 74 to demonstratehow the baffle 74 is affixed in the airfoil 60. The first platform 62includes an opening 90 that opens into the internal core cavity 70 (theforward core cavity 70 a in this example). There is a land region 62 athat circumscribes the opening 90. For instance, the land region 62 a isa relatively smooth band around the opening 90. The tube 76 of thebaffle 74 extends in the forward core cavity 70 a.

The flange ring 82 of the attachment portion 78 is congruent orsubstantially congruent with the land region 62 a. For instance, theland region 62 a may be contoured and thus the flange ring 82 may beidentically contoured. The flange ring 82 is affixed to the firstplatform 62 at the land region 62 a. For example, the flange ring 82 iswelded at a weld joint 82 a to the land region 62 a. The weld joint 82 ais endless around the flange ring 82 and land region 62 a to provide acontinuous, airtight bond there between. The weld joint 82 a may beformed by laser welding. In this regard, the continuous, relativelysmooth shape of the flange ring 82 facilitates laser welding incomparison to complex geometries that include many low angle corners.For example, the flange ring 82 has only rounded perimeter apexes,designated at 82 b. In the illustrated example (FIG. 4A), the flangering 82 has four edge perimeter apexes 82 b, which facilitates laserwelding in comparison to baffles that have tabs around the perimeter andthus many corners.

Similar to the weld joint 88, the weld joint 82 a may include a weldbead that bonds the flange ring 82 and the land region 62 a together. Inthe fixed position, the baffle 74 is positioned with a gap between thebaffle 74 and the outer wall 68. Most typically, this gap will beuniform or substantially uniform throughout the forward core cavity 70a. The gap provides an impingement stand-off distance to facilitateimpingement cooling.

The components of the baffle 74 may be formed using severalmanufacturing techniques. For example, pressure-forming involves using afluid pressure to force a sheet of material into the shape of anadjacent mold. Pressure-forming is not conducive to forming highlycontoured sections like the flange ring 82. Pressure-forming, which isconducive to forming relatively simple shapes, can be used to form thetube 76. Deep drawing involves using tensile stress to stretch andplastically deform a metal stock workpiece. Deep drawing, which isconducive to forming highly contoured shapes, can be used to form thecontoured shape of the attachment portion 78. The tube 76 and theattachment portion 78 may be formed using different metalworkingprocesses but can then be welded together at the weld joint 88, such asby laser welding. The cover 80 may also be welded to the tube 76. Thebaffle 74 can then be installed into the airfoil 60 and laser welded tothe land region 62 a of the first platform 62.

The baffle 74 has only the single weld joint 88 and no other weld seams.Additionally, the congruent shape of the flange ring 82 and the landregion 62 a permits laser welding, thereby providing complete sealingbetween the baffle 74 and the platform 62.

FIG. 7A shows an isolated view of another example baffle 174, and FIG.7B shows an expanded view of the various sections of the baffle 174. Inthis disclosure, like reference numerals designate like elements whereappropriate and reference numerals with the addition of one-hundred ormultiples thereof designate modified elements that are understood toincorporate the same features and benefits of the correspondingelements. The baffle 174 is formed at least of a tube 176 and anattachment portion 178.

The tube 176 includes a first tube end 176 a and a second tube end 176b. In this example, the first tube end 176 a is a flared end. Theattachment portion 178 also does not have the tapered neck portion 86 ofthe attachment portion 78. Rather, the funnel or funnel-like shape isprovided by the flared first end 176 a of the tube 176. The flared firstend 176 a is connected directly to the flange ring 82 of the attachmentportion 178 at the weld joint 88. The tube 176 and the attachmentportion 178 may overlap, similar to as shown in FIG. 5 .

Although a combination of features is shown in the illustrated examples,not all of them need to be combined to realize the benefits of variousembodiments of this disclosure. In other words, a system designedaccording to an embodiment of this disclosure will not necessarilyinclude all of the features shown in any one of the Figures or all ofthe portions schematically shown in the Figures. Moreover, selectedfeatures of one example embodiment may be combined with selectedfeatures of other example embodiments.

The preceding description is exemplary rather than limiting in nature.Variations and modifications to the disclosed examples may becomeapparent to those skilled in the art that do not necessarily depart fromthis disclosure. The scope of legal protection given to this disclosurecan only be determined by studying the following claims.

What is claimed is:
 1. An airfoil comprising: an airfoil section havingan airfoil wall defining leading and trailing ends and first and secondsides joining the leading and trailing ends, the first and second sidesspanning in a longitudinal direction between first and second ends, theairfoil wall circumscribing an internal core cavity; a platform attachedwith the first end of the airfoil wall, the platform including anopening that opens into the internal core cavity and a land regioncircumscribing the opening; and a baffle formed of a tube and anattachment portion, the tube extending in the internal core cavity andthe attachment portion having a flange ring affixed to the platform atthe land region.
 2. The airfoil as recited in claim 1, wherein the tubeand the attachment portion are connected to each other at a weld joint.3. The airfoil as recited in claim 2, wherein the tube and theattachment portion overlap at the weld joint.
 4. The airfoil as recitedin claim 2, wherein the weld joint is continuous around the tube.
 5. Theairfoil as recited in claim 2, wherein the attachment portion includes atapered neck portion, and the tapered neck portion is connected to thetube at the weld joint.
 6. The airfoil as recited in claim 5, whereinthe tube and the tapered neck portion overlap at the weld joint.
 7. Theairfoil as recited in claim 6, wherein the tube defines a first tube endand a second tube end, the first tube end is connected in the weldjoint, and further comprising a cover connected to the second tube end.8. The airfoil as recited in claim 1, wherein the flange ring has fourperimeter apexes.
 9. The airfoil as recited in claim 8, wherein theattachment portion includes a tapered neck portion, and the tapered neckportion and the tube are connected to each other at a weld joint.
 10. Agas turbine engine comprising: a compressor section; a combustor influid communication with the compressor section; and a turbine sectionin fluid communication with the combustor, the turbine section having aturbine airfoil that includes an airfoil section having an airfoil walldefining leading and trailing ends and first and second sides joiningthe leading and trailing ends, the first and second sides spanning in alongitudinal direction between first and second ends, the airfoil wallcircumscribing an internal core cavity, a platform attached with thefirst end of the airfoil wall, the platform including an opening thatopens into the internal core cavity and a land region circumscribing theopening, and a baffle formed of a tube and a continuous flange, the tubeextending in the internal core cavity and the continuous flange beingaffixed to the platform at the land region.